Compile the RecursiveASTVisitor callbacks test with "/bigobj"

Summary:
This file was exceeding a limit in MSVC:

fatal error C1128: number of sections exceeded object file format limit: compile with /bigobj

Reviewers: erichkeane

Reviewed By: erichkeane

Subscribers: jmorse, gribozavr2, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D82766